Project 449: M. R. Stocker. 2010. A new taxon of phytosaur (Archosauria: Pseudosuchia) from the Late Triassic (Norian) Sonsela Member (Chinle Formation) in Arizona, and a critical reevaluation of Leptosuchus Case, 1922. Palaeontology. 53 (5):997-1022.

Abstract

Leptosuchus Case 1922 (Reptilia: Phytosauria) from the Late Triassic of the American West is represented by many specimens. Here, I present complete morphological descriptions of the skull material of a new taxon from the Sonsela Member (Chinle Formation) of Petrified Forest National Park, Arizona, with the first rigorous phylogenetic analysis focused on the interrelationships of Leptosuchus. The new taxon is recovered as the sister taxon to Pseudopalatinae. It possesses one unambiguous synapomorphy (the ‘septomaxillae’ form part of the lateral borders of the nares) and shares the presence of a subsidiary opisthotic process with Pseudopalatinae. The new taxon does not fall within the restricted clade Leptosuchus. In my analysis, the previously proposed, but undemonstrated, sister taxon relationship between Angistorhinus and Rutiodon is not supported, Paleorhinus is recovered as paraphyletic, and a subset of taxa traditionally included within Leptosuchus are found to be more closely related to Pseudopalatinae, rendering Leptosuchus paraphyletic. ‘Leptosuchus’ adamanensis emerges as sister taxon to Smilosuchus gregorii and is here referred to as Smilosuchus adamanensis nov. comb., and ‘Machaeroprosopus’ lithodendrorum is also transferred to Smilosuchus lithodendrorum nov. comb.. Documentation of the variation present within Phytosauria, and specifically within Leptosuchus sensu lato, demonstrates higher diversity within Phytosauria than previously appreciated and places the character states previously proposed for Pseudopalatinae into a broader context of shared characters.


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Article DOI: doi: 10.1111/j.1475-4983.2010.00983.x

Project DOI: 10.7934/P449, http://dx.doi.org/10.7934/P449
This project containsMatrices
  • 1 Media
  • 1 Matrix
  • 1 Document
  • 25 Taxa
  • 43 Characters


Download Project SDD File
Total scored cells: 766
Total media associated with cells: 0
Total labels associated with cell media: 0
Characters
Total characters: 43
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 105
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:43/0
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MorphoBank Project 449


    Members

    member name taxa specimens media chars character
    media
    labels
    cell scorings
    (scored, NPA, "-")
    cell
    medialabels
    rules
    Michelle Stocker
    Project Administrator
    Last logged in 10/16/14
    24014300766
    (766, 0, 0)
    000
    MorphoBank Curator
    Full membership
    Last logged in 11/18/14
    1000000
    (0, 0, 0)
    000


    Taxonomic Overview for Matrix 'M1029' (24 Taxa)

    taxon unscored
    cells
    scored
    cells
    no cell
    support
    NPA
    cells
    "-" cellscell images labels on
    cell images
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    [1] † Euparkeria capensis
    Last Modified in 10/16/14
    8353500002
    [2] † Paleorhinus scurriensis
    Last Modified in 10/16/14
    18252500002
    [3] † Paleorhinus bransoni
    Last Modified in 10/16/14
    5383800002
    [4] † Paleorhinus sawini
    Last Modified in 10/16/14
    13303000002
    [5] † Brachysuchus megalodon
    Last Modified in 10/16/14
    10333300002
    [6] † Angistorhinus
    Last Modified in 10/16/14
    10333300002
    [7] † Rutiodon carolinensis
    Last Modified in 10/17/14
    12313100002
    [8] † Phytosaurus doughtyi
    Last Modified in 10/16/14
    24191900002
    [9] † Leptosuchus crosbiensis
    Last Modified in 10/16/14
    7363600002
    [10] † Leptosuchus imperfecta
    Last Modified in 10/16/14
    26171700002
    [11] † Leptosuchus studeri
    Last Modified in 10/16/14
    4393900002
    [12] † Leptosuchus adamanensis
    Last Modified in 10/16/14
    2414100002
    [13] † Machaeroprosopus lithodendrorum
    Last Modified in 10/16/14
    10333300002
    [14] † Machaeroprosopus zunii
    Last Modified in 10/16/14
    24191900002
    [15] † Smilosuchus gregorii
    Last Modified in 10/17/14
    3404000002
    [16] PEFO 31218
    Last Modified in 12/05/13
    15282800002
    [17] † PEFO 34239
    Last Modified in 10/17/14
    18252500002
    [18] † AMNH fr 30646
    Last Modified in 10/17/14
    2414100002
    [19] † PEFO 34034
    Last Modified in 10/17/14
    17262600002
    [20] † Leptosuchomorpha
    Last Modified in 11/17/14
    2414100002
    [21] † Pseudopalatus mccauleyi
    Last Modified in 10/17/14
    3404000002
    [22] † Pseudopalatus pristinus
    Last Modified in 10/17/14
    2424100002
    [23] † Mystriosuchus westphali
    Last Modified in 10/16/14
    7363600002
    [25] † Pseudopalatus jablonskiae
    Last Modified in 10/17/14
    25181800002


    Project views

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    Total project views17894
    Project overview2977
    Media views4349Media search (3810 views); M346043 (539 views);
    Matrix views2136Matrix landing page (1935 views); Pravusuchus phylogeny (201 views);
    Taxon list6035
    Bibliography773
    Documents list1624




    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project198
    Matrix downloads4Pravusuchus phylogeny (4 downloads);
    Document downloads1Phylogenetic Characters and Character States (1 download);
    Project downloads193